---
title: Window.screenY
slug: Web/API/Window/screenY
tags:
  - API
  - CSSOM View
  - Property
  - Read-only
  - Reference
  - Window
browser-compat: api.Window.screenY
---
{{APIRef}}

The **`Window.screenY`** read-only property returns the vertical distance, in CSS pixels, of the top border of the user's browser viewport to the top edge of the screen.

> **Note:** An alias of `screenY` was implemented across modern browsers in more recent times — {{domxref("Window.screenTop")}}. This was originally supported only in IE but was introduced everywhere due to popularity.

## Syntax

```js
topWindowPos = window.screenY
```

### Returns

A number equal to the number of CSS pixels from the top edge of the browser viewport to the  top edge of the screen.

## Examples

In our [screenleft-screentop](https://mdn.github.io/dom-examples/screenleft-screentop/) example, you'll see a canvas onto which has been drawn a circle. In this example we are using {{domxref("Window.screenLeft")}}/{{domxref("Window.screenTop")}} plus {{domxref("Window.requestAnimationFrame()")}} to constantly redraw the circle in the same physical position on the screen, even if the window position is moved.

```js
initialLeft = window.screenLeft + canvasElem.offsetLeft;
initialTop = window.screenTop + canvasElem.offsetTop;

function positionElem() {
  let newLeft = window.screenLeft + canvasElem.offsetLeft;
  let newTop = window.screenTop + canvasElem.offsetTop;

  let leftUpdate = initialLeft - newLeft;
  let topUpdate = initialTop - newTop;

  ctx.fillStyle = 'rgb(0, 0, 0)';
  ctx.fillRect(0, 0, width, height);
  ctx.fillStyle = 'rgb(0, 0, 255)';
  ctx.beginPath();
  ctx.arc(leftUpdate + (width/2), topUpdate + (height/2) + 35, 50, degToRad(0), degToRad(360), false);
  ctx.fill();

  pElem.textContent = 'Window.screenLeft: ' + window.screenLeft + ', Window.screenTop: ' + window.screenTop;

  window.requestAnimationFrame(positionElem);
}

window.requestAnimationFrame(positionElem);
```

These work in exactly the same way as `screenX`/`screenY`.

Also in the code we include a snippet that detects whether `screenLeft` is supported, and if not, polyfills in `screenLeft`/`screenTop` using `screenX`/`screenY`.

```js
if(!window.screenLeft) {
  window.screenLeft = window.screenX;
  window.screenTop = window.screenY;
}
```

## Specifications

{{Specifications}}

## Browser compatibility

{{Compat}}

## See also

- {{domxref("window.screenTop")}}
- {{domxref("window.screenX")}}
